NIST creates combo microchip

New chip sensors could improve productivity of semiconductor foundries

By Kathleen Hickey

Apr 16, 2008

The National Institute of Standards and Technology (NIST) has created a microchip that combines a cryogenic sensor and a micro-refrigerator.

The new technology facilitates faster, cheaper semiconductor methods by helping reduce the proportion of flawed chips on each wafer used in the production process. The technology could also help scientists analyze material found in interstellar space, NIST said.

The NIST team used a transition-edge sensor (TES), a superconducting thin film that identifies X-ray signatures far more precisely than any other device, the Commerce Department said in a statement. The chip includes a solid-state refrigerator based on a sandwich of a metal, an insulator and a superconductor. NIST scientists invented the superconducting feature and the miniature refrigerator, according to the agency.

The combo chip is a square about ¼ inch on a side and could be used for applications ranging from detailed X-ray analysis of semiconductors to detection of microwave signals in deep space. One promising application is cheaper, simpler semiconductor defect analysis using X-rays, NIST said. Another is taking pictures of the early universe more quickly at millimeter wavelengths.

Micro-refrigerators can cool separate objects by 110 millikelvins (mK), or about 0.1 degree Celsius. TES sensors are most sensitive at about 100 mK, or 0.1 degree Celsius above absolute zero. However, those temperatures are usually reached only by using bulky, complex refrigerators.

Because the new microchip can provide some of its own cooling, it can reach the low temperature of 100 mK using a simpler refrigerator that starts at room temperature and cools down to about 300 mK, NIST lead scientist Joel Ullom said.

TES sensors enable more precise identification of the X-ray 'fingerprints' of different atoms. They are expected to be powerful tools for astronomy, useful in activities such as determining the temperature and motion of matter in space, according to NIST. The chips could also improve the analysis of semiconductor materials by helping differentiate between nanoscale contaminant particles on silicon wafers. That task could help operators of chip foundries improve the yield, or proportion of functioning chips, that each wafer can furnish.

The chips perform such analysis about 40 times better than conventional X-ray sensors made of silicon and lithium, NIST said.

NASA provided some of the support for the microchip research and development.